In optical communications using an optical transmission member such as an optical fiber and an optical waveguide, an optical transmitter module including a light emitting element such as a surface-emitting laser (for example, a vertical cavity surface emitting laser (VCSEL)), and an optical receiver module including a light receiving element such as a photodetector (for example, photodiode) have traditionally been used. The optical transmitter module includes an optical receptacle which allows light containing communication information emitted from the light emitting element to be incident on an end surface of the optical transmission member. In the meanwhile, the optical receiver module allows light containing communication information emitted from the optical transmission member to be incident on a light receiving surface of the light receiving element.
For example, PTL 1 discloses an optical transmitter module including a photoelectric conversion device in which a light emitting element and a detecting element are disposed, and an optical receptacle that optically connects the light emitting element to an end surface of an optical transmission member.
The optical module disclosed in PTL 1 includes the photoelectric conversion device and the optical receptacle. The photoelectric conversion device includes the light emitting element and the detecting element fixed on a substrate by wire bonding using a wire. The optical receptacle includes a first optical surface on which light emitted from the light emitting element is incident, a second optical surface which allows light traveling inside the optical receptacle to be emitted toward the end surface of the optical transmission member, a reflective surface which reflects light incident on the first optical surface toward the second optical surface, a light separation part which separates light reflected on the reflective surface into monitor light that advances toward the light receiving element and signal light that advances toward the end surface of the optical transmission member, and a third optical surface which allows the monitor light to be emitted toward the detecting element.
In the optical module disclosed in PTL 1, light emitted from the light emitting element and incident on the first optical surface is reflected on the reflective surface toward the light separation part. The light reflected on the reflective surface is separated into the signal light and the monitor light by the light separation part. The signal light separated at the light separation part is emitted from the second optical surface toward the end surface of the optical transmission member. In the meantime, the monitor light separated at the light separation part is emitted from the third optical surface toward a light receiving surface of the detecting element.